1、BSI Standards PublicationBS ISO 20647:2015Infant formula and adultnutritionals Determinationof total iodine Inductivelycoupled plasma massspectrometry (ICP-MS)BS ISO 20647:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 20647:2015.The UK participation in i
2、ts preparation was entrusted to Technical Committee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are r
3、esponsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015ISBN 978 0 580 90423 3 ICS 67.050 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Sta
4、ndards Policy and Strategy Committee on 30 November 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 20647:2015Infant formula and adult nutritionals Determination of total iodine Inductively coupled plasma mass spectrometry (ICP-MS)Formules infantiles et produits
5、 nutritionnels pour adultes Dtermination de la teneur en iode total Spectromtrie de masse avec plasma couplage inductif (ICP-SM)INTERNATIONAL STANDARDFirst edition2015-11-01Reference numbersISO 20647:2015(E)IDF 234:2015(E)ISO20647IDF234 ISO and IDF 2015BS ISO 20647:2015ISO 20647:2015(E)IDF 234:2015(
6、E)ii ISO and IDF 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO and IDF 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photoc
7、opying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright office International Dairy FederationCh. de Blandonnet 8 CP 401 Silver Building Bd A
8、uguste Reyers 70/B B-1030 BrusselsCH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11 Tel. + 32 2 325 67 40Fax +41 22 749 09 47 Fax + 32 2 325 67 41copyrightiso.org infofil-idf.orgwww.iso.org www.fil-idf.orgBS ISO 20647:2015ISO 20647:2015(E)IDF 234:2015(E)Forewords .iv1 Scope . 12 Principle 13
9、 Reagents and materials . 14 Apparatus . 55 Procedure. 65.1 Reconstitution . 65.2 Sample preparation 65.3 Addition of reagents . 75.4 Oven digestion . 75.5 Open vessel microwave digestion 75.6 Sample filtering 85.7 Sample dilution . 85.8 Determination . 85.9 Conditioning 95.10 Calibration 95.11 Samp
10、le analysis 95.12 Data acceptability 106 Calculation .107 Precision 117.1 Interlaboratory tests . 117.2 Repeatability 117.3 Reproducibility 11Annex A (informative) Precision data 12Bibliography .13 ISO and IDF 2015 All rights reserved iiiContents PageBS ISO 20647:2015ISO 20647:2015(E)ForewordsISO (t
11、he International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical commit
12、tee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotech
13、nical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted
14、in accordance wit the editorial rules of ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Deta
15、ils of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an en
16、dorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee respons
17、ible for this document is ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products and the International Dairy Federation (IDF), in collaboration with AOAC INTERNATIONAL. It is being published jointly by ISO and IDF and separately by AOAC INTERNATIONAL. The method described in this Intern
18、ational Standard is equivalent to the AOAC Official Method 2012.15: Total iodine in infant formula and adult/pediatric nutritional formula inductively coupled plasma-mass spectrometry.IDF 234:2015(E)iv ISO and IDF 2015 All rights reservedBS ISO 20647:2015ISO 20647:2015(E)IDF (the International Dairy
19、 Federation) is a non-profit private sector organization representing the interests of various stakeholders in dairying at the global level. IDF members are organized in National Committees, which are national associations composed of representatives of dairy-related national interest groups includi
20、ng dairy farmers, dairy processing industry, dairy suppliers, academics and governments/food control authorities.ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis and sampling for milk and milk products. Since 2001, ISO and IDF jointly publish their In
21、ternational Standards using the logos and reference numbers of both organizations.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IDF shall not be held responsible for identifying any or all such patent rights. Details of any pate
22、nt rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute and endorsement.ISO
23、20647 | IDF 234 was prepared by the IDF Standing Committee on Analytical Methods for Composition and the ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, in collaboration with AOAC INTERNATIONAL. It is being published jointly by ISO and IDF, and separately
24、 by AOAC INTERNATIONAL. The method described in this International Standard is equivalent to the AOAC Official Method 2012.15: Total iodine in infant formula and adult/pediatric nutritional formula inductively coupled plasma-mass spectrometry.All work was carried out by the ISO-IDF Project Group C37
25、 of the Standing Committee on Analytical Methods for Composition under the aegis of its project leader, Mr Erik Konings (CH).IDF 234:2015(E) ISO and IDF 2015 All rights reserved vBS ISO 20647:2015BS ISO 20647:2015Infant formula and adult nutritionals Determination of total iodine Inductively coupled
26、 plasma mass spectrometry (ICP-MS)WARNING The use of this International Standard can involve hazardous materials, operations and equipment. This International Standard does not purport to address all the safety problems associated with its use. It is the responsibility of the user of this Internatio
27、nal Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1 ScopeThis International Standard specifies a method for the quantitative determination of total iodine in infant formula and adult nutritional formula.1The metho
28、d is applicable to the measurement of total iodine in infant formula and adult nutritional formula from 0,5 g/100g to 1 500 g/100g reconstituted final product and for ready-to-feed products from 2,5 g/100 g to 1 000 g/100 g using ICP-MS.Using various infant formula and adult nutritional products, th
29、e method was subjected to an interlaboratory study. Levels obtained ranged from 3,47 g/100 g to 124 g/100 g. For all precision data related to the interlaboratory study, see Table A.1 located in Annex A.2 PrincipleDigestion occurs using a potassium hydroxide (KOH) solution in an oven or open-vessel
30、microwave system. Iodine is stabilized with ammonium hydroxide and sodium thiosulfate after digestion. The solution is brought to volume followed by filtration. The filtrate is analysed directly or after dilution by inductively coupled plasma mass spectrometry (ICP-MS).3 Reagents and materialsDuring
31、 the analysis, unless otherwise stated, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity. Equivalent chemicals and reagents may be used.3.1 KOH pellets, certified ACS grade, e.g. Fisher Scientific, Fairlawn, NJ1).NOTE KOH may contrib
32、ute background levels of iodine.3.2 Ammonium hydroxide (NH4OH), 28 % to 30 % (m/m), certified ACS PLUS, Fisher Scientific1).3.3 Sodium thiosulfate (Na2S2O3), purity 99,99 %, metal basis, Fisher Scientific1).3.4 Surfactant, e.g. TritonX-100, Sigma, St. Louis, MO1).3.5 Concentrated nitric acid (HNO3),
33、 Optima, high purity, Fisher Scientific1).3.6 Perchloric acid (HClO4), 70 % (m/m).1) This is an example of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by either ISO or IDF of the product nam
34、ed. Equivalent products may be used if they can be shown to lead to the same results.INTERNATIONAL STANDARDISO 20647:2015(E)IDF 234:2015(E) ISO and IDF 2015 All rights reserved 1BS ISO 20647:2015ISO 20647:2015(E)3.7 Purified water, 18 M/cm.3.8 Reference standards3.8.1 Iodide standard solution in wat
35、er, mass concentration = 1 000 g/ml, SPEX CertiPrep1).3.8.2 Iodide standard solution in 1 % triethylamine (TEA), = 1 000 g/ml, Inorganic Ventures1).3.8.3 Standard Reference Material (SRM), National Institute of Standards and Technology (NIST) SRM 1849a, Infant/Adult Nutritional Formula.Either stock
36、iodide reference solutions may be used for intermediate and working standard solutions preparation. The remaining source may be used as a continuing calibration verification (CCV) standard. Equivalent reference standards may be substituted. Iodide may be referred to as iodine throughout this Interna
37、tional Standard.3.9 Internal standards3.9.1 Praseodymium (Pr) standard solution in 5 % HNO3, = 10 g/ml, Inorganic Ventures1).Individual values of iodine are reported for each test sample using praseodymium as the internal standard. Equivalent stock internal standard solutions may be substituted.3.10
38、 Preparation of reagent solutions3.10.1 GeneralPrepare all reagent solutions as recommended by either mass per volume or volume per volume. Adjusting for purity and/or concentration is not required.3.10.2 KOH solution, = 50 g/lDissolve 25 g of KOH pellets in an appropriate amount of purified water,
39、then dilute to 500 ml with purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store this solution at room temperature. Reagent expires 6 months after preparation date.3.10.3 Stabilizer concentrateDissolve 5 g of Na2S2O3in an appropriate amount of purified wa
40、ter, add 50 ml of NH4OH, then dilute to 500 ml with purified water. The resulting concentration is 10 % NH4OH and 1 % Na2S2O3in purified water. Store this solution at room temperature. Reagent expires 6 months after preparation date.3.10.4 Wash solution (rinse)Dissolve 2 g of surfactant (3.4) in an
41、appropriate amount of purified water, add 20 ml of NH4OH, then dilute to 2 000 ml with purified water. The resulting concentration is 1 % NH4OH and 0,1 % surfactant in purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store this solution at room temperature
42、. Reagent expires 6 months after preparation date.3.10.5 DiluentDissolve 10 g of KOH pellets and 0,4 g Na2S2O3in an appropriate amount of purified water, add 4 ml NH4OH, then dilute to 2 000 ml with purified water. Store this solution at room temperature. Reagent expires 6 months after preparation d
43、ate.IDF 234:2015(E)2 ISO and IDF 2015 All rights reservedBS ISO 20647:2015ISO 20647:2015(E)Alternatively, for a smaller volume, dilute 50 ml of 5 % KOH and 10 ml of stabilizer concentrate (3.10.3) to 500 ml with purified water. The resulting concentrations for both preparations are 0,5 % KOH, 0,2 %
44、NH4OH, and 0,02 % Na2S2O3in purified water. Store this solution at room temperature. Reagent expires 6 months after preparation date.3.10.6 Conditioning solutionPrepare by aliquoting 25 ml of KOH solution (3.10.2), then dilute to 250 ml with purified water. Use this solution to prepare the instrumen
45、t for analysis. The resulting concentration is 5 g/l KOH. Store this solution at room temperature. Reagent expires 6 months after preparation date.3.10.7 Carrier solutionThis solution is equivalent to the wash solution (3.10.4). The carrier solution is used to deliver the sample solution to the nebu
46、lizer through the ICP-MS autosampler introduction system. The carrier solution is introduced via a peristaltic pump using 0,76 mm inside diameter (id) two-stop polyvinyl chloride pump tubing. Store this solution at room temperature. Reagent expires 6 months after preparation date.3.11 Preparation of
47、 standard solutions3.11.1 GeneralStock solutions are stable until the end date indicated on the certificate of analysis. Intermediate stock standard, calibration standard, continuing calibration verification and internal standard solutions are stable at room temperature until the earliest expiration
48、 date of all components used to prepare the solution. These solutions are ready to use for analysis. Do not subject them to any of the various procedures used to prepare actual samples (i.e. infant formulas and adult nutritionals) for analysis.3.11.2 Stock iodine and praseodymium solutionsPurchase o
49、f stock iodine and praseodymium standard solutions with accompanying certificates of analysis is recommended.3.11.3 Intermediate stock standard (ISS) iodine solutionsPrepare the intermediate stock standard iodine solutions according to Table 1.These ISS solutions are used for calibration standard preparation and are typically prepared according to Table 1. The ISS concentrations presented are nominal. Using the stock iodine concentration found on the certificate of analysis, determine the exact concentration
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